ARM: pxa: activate pinctrl for device-tree machines

Pincontrol is not yet ready for all PXA platforms.
For example, a legacy platform, if PINCTRL was activated, will fail its
calls to gpio_request() or gpio_direction_output(), as the pinctrl
driver might not be available, such as for pxa25x and pxa3xx.

As a step forward, activate pincontrol for all device-tree available
machines, ie. pxa27x device-tree based and pxa3xx device-tree based.

If it appears later that pincontrol is also required for legacy
platforms and if the mfp->pinctrl conversion can be achieved, then
PINCTRL will be activated for the whole PXA architecture.

Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Linus Walleij <linus.walleij@linaro.org>